Lagriinae

Latreille, 1825

Long-jointed Beetles

Tribe Guides

5

Lagriinae is a of darkling beetles within the Tenebrionidae, comprising more than 270 grouped into 11 tribes. are medium-sized (5–12 mm) with characteristic Tenebrionidae features including a 5-5-4 tarsal formula and antennal bases concealed by . The subfamily is notable for its defensive with Burkholderia bacteria that produce the antifungal compound lagriamide, protecting and larvae from antagonistic fungi. This symbiosis has evolved through multiple independent horizontal acquisition events rather than strict co-diversification.

Statira dolera by (c) jimeckert49, some rights reserved (CC BY). Used under a CC-BY license.Statira nigromaculata by (c) Katja Schulz, some rights reserved (CC BY). Used under a CC-BY license.Statira nigromaculata by (c) jimeckert49, some rights reserved (CC BY). Used under a CC-BY license.

Pronunciation

How to pronounce Lagriinae: //ləˈɡriː.ɪ.naɪ//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other Tenebrionidae by the combination of: deeply that often partially surround antennal bases; last antennal segment enlarged (longest or widest); at least as broad as pronotum, often constricted behind eyes; pronotum narrower than elytral base, broadest at base with sinuate sides. The 5-5-4 tarsal formula and concealed antennal bases are -level characters shared with other Tenebrionidae. Some are mimics of other families: Arthromacra resembles Oedemeridae, Rhypasma resembles Silvanidae, Casnonidea apicicornis resembles Chrysomelidae, Statira resembles Carabidae, and Paratenetus punctatus resembles Coccinellidae.

Images

Appearance

are mostly medium-sized, 5–12 mm in length. They exhibit typical Tenebrionidae characteristics: 5-5-4 tarsal formula (five tarsomeres on fore- and midlegs, four on hind legs) and antennal bases concealed by (lateral projections of the ). are usually deeply (notched) and in many partially surround the antennal bases. The last antennal segment is either the longest or widest segment, often sexually dimorphic. The head tends to be at least as broad as the pronotum and is often constricted behind the level of the eyes. The pronotum is generally much narrower than the base of the , broadest at its base, with sinuate or otherwise constricted sides. Some species display pronounced , including (wingless) females in certain subgenera.

Habitat

Associated with vegetation; larvae occur in decaying vegetation, stumps, and under bark. found on plants, with some noted as crop pests (e.g., soybean). -harboring species can be found on plants and in soil environments where symbiotic Burkholderia bacteria can be acquired.

Distribution

distribution with records from all major biogeographic regions. Documented from Brazil, Japan, Germany, Spain, Australia, Morocco, Algeria, China (including Tibet, Guangxi, Guizhou, Hong Kong, Hunan, Sichuan), and North America.

Diet

Larvae feed in decaying vegetation. Specific feeding habits are not well documented; Lagria villosa is noted as a soybean pest, suggesting .

Host Associations

  • Burkholderia - defensive -eroded bacteria producing antifungal lagriamide; housed in glandular structures of female ovipositor and secreted onto
  • Antagonistic fungi - target of defenseLagriamide protects and larvae from fungal
  • Soybean and other plants - plantSite of transfer; symbionts can survive on plant tissues for several days
  • Soil microbiota - potential sourceEnvironmental acquisition of possible from soil and plant environment

Life Cycle

are deposited with symbiotic Burkholderia bacteria secreted from glandular structures associated with the female ovipositor. Larvae develop in decaying vegetation, stumps, and under bark. protect both egg and larval stages from antagonistic fungi. Specialized symbiont-harboring structures likely evolved between 55–82 million years ago based on fossil evidence.

Behavior

Females secrete defensive onto during oviposition. Some exhibit pronounced with females. Certain (e.g., Eleodes relatives within Tenebrionidae) perform characteristic 'headstand' defensive postures when disturbed, though this is more documented in related tenebrionid groups.

Ecological Role

Defensive mutualism with Burkholderia protects early life stages from fungal antagonists. Some are agricultural pests (e.g., on soybean). Decomposer role in larval stage processing decaying vegetation. Symbiont transfer to and from plant tissues may influence plant-associated microbial .

Human Relevance

Some are crop pests, notably Lagria villosa on soybean. Subject of significant research interest regarding evolution of defensive , , and erosion in bacterial . The lagriamide biosynthetic has potential biotechnological applications.

Similar Taxa

More Details

Symbiont Evolution

The lagriamide-producing represents a dynamic evolutionary history with at least four independent horizontal acquisition events of closely related Burkholderia across 7 from 5 countries on 4 continents. This contrasts with the pattern of strict and host-symbiont co-diversification seen in older intracellular symbioses. Each independent acquisition was followed by convergent erosion in the symbiont lineage.

Genome Erosion

The Burkholderia in Lagriinae show extensive reduction including loss of repair , primary metabolism genes, and accumulation of pseudogenes and transposases. Despite this erosion, the lagriamide biosynthetic gene cluster is retained and functional. Plant-associated Burkholderia relatives retained large genomes but secondarily lost the lagriamide gene cluster.

Taxonomic History

Lagriinae was formerly treated as a separate (Lagriidae) but is now classified as a of Tenebrionidae. The group includes more than 270 organized into 11 tribes, with significant diversity in Asia, Africa, and the Americas.

Tags

Sources and further reading